Wood-preserving composition



Patented Dec. 5, 1939 2,182,080 I WOOD-PRESERVING COMPOSITION -Ira Hatfield, Webster Groves, MoQassignor to Monsanto Chemical Company, St. Louis, Mo., a corporation of Delaware No Drawing.

9 Claims.

The present invention relates to a process of preserving wood and similar cellulosic materials subject to attack by stain, decay and mold fungi, as well as other micro-organisms, and refers particularly to a composition for this purpose.

Pentachlorophenol, tetrachlorophenois and, to a lesser extent, lower poly chlorophenols, have been found to be especially useful toxic substances for the treatment of wood and wood prod-- ucts to preserve them from attack by molds and micro-organisms such as are responsible for staining and decay. For finished mill work, tetrachlorophenols and pentachlorophenol have been applied to the wood in the form of a liquid composition by dipping. One of the principal requirements of the solvent. or carrier which was to be used in such coating or impregnating compositions was that it be readily volatile. Solvents which were used included pine oil, kerosene, Stoddard solvent naphtha, alcohols, etc. It was also essential that the liquid composition should penetrate and spread in the wood when dipped therein. For this purpose various liquids called penetrants have been added to facilitate penetration of the end grain of the wood, and other materials called Spreaders, have been added to aid spreading in the wood at right angles to the grain.

However, considerable diificulty has been encountered in using liquid tetrachlor'ophenol and pentachlorophenol compositions containing volatile solvents such as solvent naphtha, pine oil, alcohols, etc., for wood coating and impregnation, since, as the solvents volatilize, the polychlorophenols creep or work to the surface of the wood and so-called blooming or crystallization ocours. The crystalline deposit which thus forms as a bloom on the surface, besides having an objectionable appearance on the wood, is easily 4'0 disengaged by rubbing, brushing or even blowing. When blooming occurs, as it invariably does with such compositions containing volatile solvents, the full value of the treatment is thus not afforded. Besides representing a loss of toxic material when the crystals come to the surface of the wood, disengaged crystals from the wood surface may present a health hazard.

The principal object of the present invention is to provide a liquid wood-preserving composi- 5 tion containing polychlorophenols which will not bloom on wood or similarmaterials coated or impregnated therewith, and will thus reduce the health hazard and increase the emcacy of a treatment with polychlorophenols. It is a further 55 object of the invention to provide an improved' liquid composition for this purpose and a method for its application which will produce deeper penetration of the wood and thus provide better protection against stain, decay and similar attacks by micro-organisms.

of 5 parts of rosin and 5 parts of pentachlorophe- Application December 27, 1937, Serial No. 181,989

I have discovered that the above objects are admirably realized by using a liquid composition comprising rosin or a similar resinous substance, toxic agents such as polychlorophenols, for example, tetrachlorophenols or pentachlorophenol, and a solvent such as a high-boiling, relatively non-valatile oil such as petroleum fuel oil or similar material. An example of sucha liquid wood-preserving composition is one consisting nol dissolved in 90 parts of Shell Petroleum Corporations No. 2 Mid Continent fuel oil. Such compositions are applied to the wood either by dipping, spraying or brushing, and the solvent instead of evaporating rapidly, partially remains onthe surface of the wood for a short period and gradually penetrates into the wood. The composition acts both as a penetrant and spreader in the body of the wood.

Heretofore in using liquid wood-preserving compositions containing volatile solvents, brushing or spraying were poor methods of applying the compositions because sufficient penetration could not be achieved. It was thus necessary to use dipping treatments in which the wood was sub- 25 jected to contact with liquid compositions for periods differing according to the degree of penetration desired, which period might vary from several minutes to a matter of hours. These dipping treatments were in realitysoaking treat- 3 ments. By using the coating composition of the present invention the coating composition may be spread on the wood by brushing, spraying or dipping. The composition slowly penetrates into the coated wood as the surface becomes dry. The 35 ful penetration and distribution of the treating solution continues over a period of from several hours to a day or more, even after the surface is dry. The penetration of the wood by the liquid composition is deeper than that obtained with 4 soaking in volatileliquid compositions for periods usually permitted in dipping treatments. Greater quantities of wood can therefore be treated by dipping in any particular dipping 'vat in a given period according to the invention, 4. since the effectiveness of the treatment is not dependent solely upon the period the wood remains submerged in the treating solution. The solution continues to penertate into the wood after thewood is removed from the liquid. Since 5 the solvents used in the improved compositions possess high flash points the fire hazard is considerably reduced. The composition is also suitable for application to wood by pressure treatments according to the methods known in the art.

. The rosin or similar resinous substances in the composition has several functions. Liquid compositions without rosin when made with highboiling oils, forexample, Shell No. 2 fuel oil, still go produce blooming on the surface of the wood, although a slight reduction in tendency is noted with various oils of this character. However, I have discovered that rosin and similar resinous substances added in suitable proportions completely suppress blooming. Furthermore, the rosin has an additional function in solubilizing the toxic phenol, for example, pentachlorophenol and tetrachlorophenols. Compositions prepared according to my invention have a shorter drying time on the wood, that is, the surface of wood treated therewith is drier in a shorter period of time that that treated with a similar composition not containing rosin, and the period required for penetration of the composition throughout the wood is not lengthened. Wood treated with the composition of my invention shows just as deep penetration as that treated by means of compositions not containing rosin,

g0 and since my invention also contemplates the use of particular solvents which have both a spreading and a penetrating action, wood thus treated exhibits deeper penetration than that resulting from treatment with compositions prepared withvolatile solvents or compositions containing volatile solvents together with so-called spreaders and penetrants.

In using phenolic preserving compositions, the blooming and failure of such compositions to penetrate have seriously afiected the so-called paintability and puttiability of the treated wood, that is, paint and putty when applied to the wood would not adhere firmly and in the course of time even that which had adhered would gradually become disengaged. With the compositions of the present invention, the paintability and puttiability of the wood is not substantially impaired after treatment. Since the compositions dry rapidly when applied to a wood surface, the wood is ready for painting and the application of putty shortly after treatment, and since the surfaces are dry and free from bloom rather than oily and coated with crystals, putty and paint adhere firmly thereto.

In producing the liquid coating and impregnating compositions of the invention I dissolve approximately 5% by weight of a tetrachlorophenol or technical mixtures of tetrachlorophenols, or pentachlorophenol in 90% by weight of a fuel oil or a similar petroleum hydrocarbon oil, preferably one having a high flash point. Smaller proportions of the polychlorophenol component may be used but the resulting impregnated wood is not as completely protected; Greater proportions of the toxic materials in the liquid compositions may be used but these greater additions are, of course, limited to some extent by the solvent power of the petroleum oil and by economic considerations. The compositions must be stable and must completely retain all the polychlorophenol without any separation or crystallization at outdoor temperatures. For prolonged fungicidal protection a wood impregnated with a composition containing 5% of polychlorophenol according to the method of the invention is eminently satisfactory.

The petroleum oils which I prefer for the purposes of the invention are those having characteristics within the approximate ranges given hereinbelow: p

Gravity A. P. I. at 60 F -40 Flast point A. S. T. M 140 F. and higher Viscosity Saybolt Universal at 100 F. -40

A. S. T. M. distillation range 300-750 F.

Petroleum solvents boiling at lower ranges than those hereinabove specified may be used provided they dissolve the desired proportion of the toxic chemical. The odor and color of the 011 must also be considered for the particular application. For some purposes, odorous oils or oils of dark color are not objectionable but for bright lumber of the highest grade, light-color odorless oils are essential. Oils of high boiling range are desirable, as hereinbefore stated.

Although petroleum oils have ben specifically described, high-boiling chlorinated solvents and aliphatic as well as aromatic solvents may be used. The rosin or similar resinous material has proven effective in preventing blooming tendency which the solvents might engender. Of course, economic considerations are in favor of the use of petroleum solvents or their mixtures with small proportions of other solvents.

In using the compositions of the invention, different solvent mixtures may be used in the treatment of woodproducts of different thicknesses. Thus, for example, a mixture of low-boiling and high-boiling petroleum solvents is eminently suitable for the preparation of compositions for treatment of thin wood boards. For thicker boards, greater proportions of high-boiling solvents are desirable to facilitate deeper penetration.

Rosin in my compositions may be replaced by other resinous materials soluble in the solvents used and compatible with the phenol. Cumarone-indene resins, petroleum resins such as that sold under the trade name Santo-Resin, rosin residues, ester gum, rosin esters, petroleum tar resins and resins derived from rosin such as that designated by the trade name Vinsol may be used to replace the rosin partially or completely.

The proportions used in the composition may be varied. The possible variation will be limited by the solubility of the particular toxic substance in the particular solvent. The ratio of rosin or other resinous material to toxic substance necessary to suppress blooming of the toxic substance in the particular solvent and to provide compositions of desirable surface-drying time will also be variable.

The invention is applicable to the treatment of wood and wood products which are particularly subject to decay and stain especially those materials which are subjected to humid and moist conditions which favor the development of stain and decay. Cellulosic materials such as cloths, papers, wall boards and the like which are also subject to attack by micro-organisms can be similarly treated with these compositions.

The compositions may be modified by the addition thereto of secondary materials such as wetting agents, water-repellents, insect-repellents, fire retardants, substances which exert a synergistic action on the chlorinated phenols and other materials having favorable action on the impregnation or penetration of the composition or have a desirable action in further protecting or enhancing the value of the treated article.

In this specification and in the claims tetrachlorophenol is to be understood to signify any of the isomers or a mixture of the isomers. It is also to be understood that the foregoing description is but a preferred embodiment of the invention and that changes and modifications may be made therein without departing substantially from the invention which is defined in the appended claims.

Although the foregoing description has been specifically directed to the use of tetrachlorophenols and pentachlorophenol as the toxic component of the composition it is evident that the blooming of compositions containing other chlorinated phenolic toxics such as chlorinated cresols, chlorinated coal tar acids, chlorinated woodtar acids, chlorinated naphthols, or chlorinated hydroxydiphenyls may likewise be prevented.

Reference is made to my copendi'ng application Serial No. 272,784 filed on May 10, 1939, which contains subject matter disclosed but not specifically claimed herein.

What I claim is:

1. A non-blooming liquid coating and impregnating composition for the treatment of wood and similar cellulosic materials to protect them from attack and decay by molds and micro-organisms, comprising a chlorinated phenol dissolved in a solvent therefor in suflicient concentration to provide, when applied to wood and similar cellulosic materials, substantial protection from attack and decay by molds and microorganisms, and having dissolved in said solvent a resinous substance that is soluble in said solvent and that is compatible with the mixture in suflicient concentration to prevent blooming on wood and similar cellulosic materials treated with the liquid composition.

2. A non-blooming liquid coating and impregnating composition for the treatment of wood and similar cellulosic materials to protect them from attack and decay by molds and microorganisms, comprising a polychlorinated phenol dissolved in a solvent therefor in suflicient concentration to provide, when applied to'wood and similar cellulosic materials, substantial protection from attack and decay by molds and microorganisms, and having dissolved in said solvent a resin selected from the group consisting of rosin, rosin residues, resins derived from rosin, cumarone-indene resins, petroleum resins and petroleum tar resins in sufficient concentration to prevent blooming on wood and similar cellulosic materials treated with the liquid composition.

3. A non-blooming liquid coating and impregnating composition for the treatment of wood and similar cellulosic materials to protect them from attack and decay by molds and microorganisms, comprising a polychlorinated phenol dissolved in a solvent therefor in sufflcient concentration to provide, when applied to wood and similar cellulosic materials, substantial protection from attack and decay by molds and microorganisms, and having rosin dissolved in said solvent in suflicient concentration to prevent blooming on wood and similar cellulosic materials treated with the liquid composition.

4. A non-blooming liquid coating and impregnating composition for the treatment of wood and similarcellulosic materials to protect them from attack and decay by molds and microorganisms, comprising a chlorinated phenol dissolved in a petroleum solvent in suflicient concentration to provide, when applied to wood and similar cellulosic materials, substantial protection from attack and decay by molds and micro organisms, and having dissolved in said petroleum solvent a resinous substance that is soluble in said solvent and that is compatible with the mixture in suflicient concentration toprevent blooming on wood and similar cellulosic materials treated with the liquid composition.

5. A non-blooming liquid coating and impregnating composition for the treatment of wood from attack and decay by molds and microorganisms, comprising a chlorinated phenol dissolved in a petroleum hydrocarbon fuel oil having a boiling range within the range of approximately 300 to 750 F. in sufficient concentration to provide, when applied to wood and similar cellulosic materials, substantial protection from attack and decay by molds and microorganisms and having rosin dissolved in said hydrocarbon fuel oil in sufiicient concentration to prevent blooming on wood and similar cellulosic materials treated with the liquid composition.

6. A non-blooming liquid coating and impregnating composition for the treatment of wood and similar cellulosic materials to protect them from attack and decay by molds and microorganisms, comprising a chlorinated phenol selected from the group consisting of tetrachlorophenols and pentachlorophenol dissolved in a solvent therefor in sufiicient concentration to provide, when applied to wood and similar cellulosic materials, substantial protection from attack and decay by molds and micro-organisms, and having dissolved in said solvent a resinous substance that is soluble in said solvent and that is compatible with the mixture in suflicient concentration to prevent blooming on wood and similar cellulosic materials treated with the liquid composition. '7. A non-blooming liquid coating and impregnating composition for the treatment of wood and similar cellulosic materials to protect them from attack and decay by molds and microorganisms, comprising a chlorinated phenol selected from the group consisting of tetrachlorophenols and pentachlorophenol dissolved in a petroleum hydrocarbon oil having a boiling range within the range of approximately 300 to 750 F. in suflicient concentration to provide, when applied to wood and similar cellulosic materials, substantial protection from attack and decay by molds and microorganisms, and having rosin dissolved in said petroleum hydrocarbon oil in suflicient concentration to prevent blooming on wood and similar cellulosic materials treated with the liquid composition.

8. A non-blooming liquid coating and impregnating composition for the treatment of wood and similar cellulosic materials to protect them from attack by molds and other micro-organisms, comprising approximately 5 parts by weight of pentachlorophenol, 5 parts by weight of rosin, and 90 parts by weight of a petroleum hydrocarbon fuel oil having a boiling range within the range of thefollowing materials in approximately the following proportions: 300 to 750 F.

9. A non-blooming liquid coating and impregnating composition for the treatment of wood .and similar cellulosic materials to protect them from attack by molds and other micro-organisms, comprising approximately 5 parts by weight of tetrachlorophenol, 5 parts by weight of rosin, and 90 parts by weight of a petroleum hydrocarbon fuel oil having a boiling range within the range of the following materials in approximately the following proportions: 300 to 750 F.

IRA HA'I'FIELD.

- and similar cellulosic materials to protect them CERTIFICATE 0F CORRECTION.

Patent No. 2,182,08- December 5: 959- IRA HATFIELD.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows; Page 1, sec d lumn, line 7, for non-valatile" read non-volatile; line 36, fo "n11" read full; line 1 9, for "penertate" read penetrate; line 57-, for "substances" read substance; page 2, first column, line 72, for "Flast" read. Flash; and second column, line 11, for "ben" read been; page 5, second column, lines Shand 61 claims Band 9 respectively, for "approximate ly" readthe following materials in approximately the following proportionsz; lines 58 and 59, claim 8, and lines 68 and 69, claim 9, for "the following materials in approximately the following proportipnsz read approximately; and that the said Letters Patent should be read with this correction therein that the same may conform to the record of the case in the Patent Office.

Signed and sealed this 6th day of February, A. D. 1910.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents. 

